Puree the turbot in a food processor then add the salt and lemon juice followed by the egg white and place into an iced bowl. Add the cream reserving 2floz for the prawns. Butter 4 ramekins. Mix the saffron with the cream, then add the prawns. Line the base and sides of the moulds with the turbot mixture. Spoon the prawn and saffron mixture into the centre, then cover with more turbot mixture. Tap moulds to remove any air and place into a double boiler. Cover and place into a pre-heated oven for approximately 20 minutes. For the prawn sauce: Melt the butter and sweat off the shallot. Add the tarragon, cover and cook. Then add the fish stock, the wine and reduce. Add the cream and bring back to the simmer, then add the capers, gherkins and cucumber and heat through. In the last minute before serving add the prawns. De-mould the turbot and place onto a warm plate. Coat with the sauce and serve. DISCLAIMER(c) Copyright 1996 - SelecTV Cable Limited. All rights reserved. Carlton Food Network http://www.cfn.co.uk/